Bearings

Sep 30, 2026
Sep 30, 2026
STATISTICS · reversal of a 30-year finding, peer-reviewed reanalysis, 2015 to 2021

A 30-Year Consensus On The Hot Hand Was Backwards

Setup. In 1985, psychologists Thomas Gilovich, Amos Tversky, and Robert Vallone tested a belief every basketball fan holds, that a player who just made several shots in a row is more likely to make the next one. They found no such pattern in real shooting data and named it the hot hand fallacy, a case study in how people see patterns in randomness.

What happened. The verdict held for three decades until 2015, when economists Joshua Miller and Adam Sanjurjo found a hidden flaw in the original method. Counting shots only after a streak already started quietly biases the sample toward misses that follow it. Once they corrected for that bias, the original 1985 data itself showed real streak shooting. A 2018 reanalysis of Golden State Warriors shooting, and a 2021 study of three-point contests, both found the same small but real effect.

Where it stands. This reversed a textbook example of human irrationality into an example of a subtle statistical trap in the researchers' own method. The debate is not fully closed. Other recent studies still find nothing, and where the effect appears, it seems limited to shots from a fixed spot, like free throws, rather than shooting during live play.

Wikipedia · Hot hand · reanalysis dated 2015 ↗
SOCIAL PSYCHOLOGY · registered replication and meta-analysis, 1988 to 2019

Smiling Causes Happiness, But The Effect Is Tiny

Setup. Darwin and William James both argued that a facial expression does not just show an emotion, it helps cause it. In 1988, psychologists Fritz Strack, Leonard Martin, and Sabine Stepper tested this by having people hold a pen between their teeth, forcing a smile, or between their lips, forcing a frown, while rating cartoons, all without ever mentioning emotion.

What happened. The smiling group rated the cartoons funnier, and the study became a fixture of introductory psychology for thirty years. In 2016, a Registered Replication Report repeated the exact experiment in 17 labs across several countries and failed to reproduce the result.

Where it stands. A 2019 meta-analysis of 138 separate studies found the effect is genuine but small, not the large, decisive force the original study suggested. Separately, patients whose frown muscles are paralyzed by botox show measurable changes in brain regions tied to emotion, and read sad sentences slower than before treatment. The honest summary sits between the two headlines: facial feedback shapes emotion a little, not a lot, and the 1988 study oversold its own size.

Wikipedia · Facial feedback hypothesis · meta-analysis dated 2019 ↗
FORENSIC PSYCHOLOGY · survey of legal professionals, contradicted by juror studies, 2006 to 2009

Lawyers Widely Believe A Jury Bias That Studies Cannot Find

Setup. After the show CSI premiered in 2000, prosecutors began describing a new problem: jurors who expected DNA and fingerprint evidence in every trial, and who reportedly acquitted when real forensic work came back thinner and slower than television had trained them to expect. News coverage of the claim exploded, and by 2009 more than 250 stories had covered it.

The finding. Belief in the effect is close to universal among legal professionals: 56 percent of surveyed prosecutors believed it almost always or always sways juries, and 81 percent believed it sways judges. But a landmark 2006 survey of over 1,000 actual jurors, and several later studies, found no correlation between crime show viewing and a juror's likelihood to convict. A separate look at conviction data across eight states found acquittal rates falling, not rising, after CSI's debut.

Where it stands. This is a documented case of legal professionals confidently diagnosing a jury bias that researchers cannot find in the actual data. Jurors do show higher general expectations for forensic evidence. That expectation has not been shown to change verdicts.

Wikipedia · CSI effect · survey dated 2006 ↗
POLITICAL SOCIOLOGY · thesis from a 1911 book by Robert Michels

Every Democratic Organization Drifts Toward Rule By The Few

Setup. In 1911, sociologist Robert Michels studied Europe's socialist parties, organizations built explicitly on democratic ideals and mass participation. He expected them to prove that popular movements could resist the pull toward elite control. Instead he found the same concentration of power at the top that traditional conservative parties had.

The argument. Michels concluded the cause was not any single party but organization itself. Any group large enough to need a bureaucracy must delegate real decisions to a small leadership, who then gain expertise, control resources, and entrench themselves regardless of the group's founding ideals. He called this the iron law of oligarchy: unavoidable in any sufficiently complex organization.

Where it stands. The thesis is a century-old argument built from historical case studies, not a measured effect, and it has genuine exceptions. A mid-century study of an American printers' union found it stayed democratic for decades. A 2009 case study argued Wikipedia resists the pattern, though a 2016 study using the same data concluded the opposite. Which organizations escape the law, and how, remains an open and actively studied question.

Wikipedia · Iron law of oligarchy · thesis dated 1911 ↗
COGNITIVE PSYCHOLOGY · peer-reviewed finding, replicated 1977 to 2015

Repeating A Claim Makes It Feel True, Even When Wrong

Setup. In 1977, researchers at Villanova and Temple gave college students the same list of sixty trivia statements three times, two weeks apart, mixed in with new statements each round. Some were true, some false, and the topics were ones students were unlikely to know anything about.

The finding. Confidence in the repeated statements climbed steadily across the three sessions, while confidence in new statements stayed flat. Later studies found the same effect even in people who already knew the correct answer, and even after they were explicitly warned that repetition proves nothing about truth. Researchers attribute this to processing fluency: a repeated statement is easier for the brain to process, and that ease of processing gets misread as a signal of truth.

Where it stands. This is a well-replicated finding spanning five decades, from the original 1977 result through recent studies on modern false news. It explains why repeated claims gain a false sheen of credibility over time in advertising, propaganda, and ordinary rumor, regardless of whether the claim was ever checked.

Wikipedia · Illusory truth effect · study dated 1977 ↗
Sep 29, 2026
GAME THEORY · a theorem published by Moshe Tennenholtz in 2004

Programs That Read Rivals' Code Can Learn To Cooperate

Setup. In the classic prisoner's dilemma, both players do better by betraying each other, even though both would gain more by cooperating, because neither can trust a promise. Program equilibrium, a concept introduced by Moshe Tennenholtz in 2004, asks what happens when players do not pick an action directly but instead submit a computer program that can read the opponent's source code and decide for them.

The finding. One simple program, CliqueBot, cooperates only if the opponent's code matches its own exactly, a plan that collapses if either side edits even a single character. A sturdier program, FairBot, instead tries to prove the opponent will cooperate before it does, using a result from mathematical logic called Löb's theorem, it can be shown that when both players submit this program, they cooperate against each other. A folk theorem shows any payoff at least as good as a player's guaranteed minimum can be reached this way.

Where it stands. This is a proven mathematical result, not an experiment, and it assumes programs can read each other's exact code, a condition ordinary negotiation never meets. It has gained new relevance now that AI agents increasingly transact with some visibility into each other's code or weights.

Moshe Tennenholtz · Wikipedia · 2004 ↗
ANCIENT HISTORY · a magazine essay built on the archaeological and isotopic record · Sep 2026

Cheap Iron, Not Bronze, Explains Empires' Fall

Setup. Around 1200 BC the great Bronze Age empires of the eastern Mediterranean, Egypt, the Hittites, Assyria, Mycenaean Greece, collapsed within a few generations. Historians usually blame drought, invaders and revolt. None of that explains the odder fact: for centuries afterward, nothing of comparable scale rose to replace them.

The argument. Patrick Fitzsimmons argues the empires never returned because the material basis of military power changed. Bronze needed tin, found only in a handful of distant deposits in modern Afghanistan, Cornwall and Iberia, so only large, organized states could reliably arm big forces. Iron ore, by contrast, is the fourth most abundant element in Earth's crust and sits visibly near the surface almost everywhere. Because iron could be produced locally, imperial centers no longer had such a strong advantage over their subject peoples. Skeletal evidence shows violence rose after iron spread, even as large empires stayed absent.

Where it stands. This is a magazine essay synthesizing archaeology and isotope-tracing research, not one new study, and historians still debate what triggered the initial 1200 BC collapse. The iron-democratization mechanism is a well evidenced explanation for why empires stayed fragmented afterward, a separate and more testable question than what caused the collapse itself.

Patrick Fitzsimmons · Works in Progress · Sep 2026 ↗
CORPORATE FINANCE · a theorem published by Franco Modigliani and Merton Miller in 1958

Debt Or Equity, A Firm's Value Stays The Same

Setup. A company can raise money by selling shares, borrowing, or some mix of the two. Business intuition treats this as a real choice with real consequences for what the company is worth, and lenders, investors and executives spend enormous effort arguing over the ideal mix of debt and equity.

The finding. Franco Modigliani and Merton Miller showed in 1958 that, in a market with no taxes, no bankruptcy costs and no informational advantage for insiders, the enterprise value of a firm is unaffected by how that firm is financed. The proof rests on arbitrage: if a levered and unlevered version of the same firm ever traded at different prices, investors could borrow or lend on their own account to capture the difference, pushing the two prices back together. Both economists later won a Nobel Prize partly for this result.

Where it stands. This is a proven theorem, not an empirical claim, and its own assumptions name where it breaks down. Once interest payments become tax-deductible, added debt raises firm value, which is exactly the boundary condition that makes real capital structure decisions matter in practice.

Franco Modigliani and Merton Miller · Wikipedia · 1958 ↗
EVOLUTIONARY GENETICS · magazine essay built on peer-reviewed genome studies · Sep 2026

A Stray Gene Insertion Turned Moths Black In 1819

Setup. Nearly half of the human genome consists of transposons, DNA sequences that can cut or copy themselves out of one spot in a genome and paste themselves somewhere else. Long dismissed as genetic junk or viral leftovers, they are now understood to sometimes drive real evolutionary change, not just accumulate as clutter.

The finding. England's peppered moths turned from speckled white to solid black after coal pollution darkened tree bark in the Industrial Revolution, a textbook case of natural selection. It took until 2016 for geneticists to find the actual mechanism. A transposon, absent in the white-winged moths, had been inserted into the beginning of this gene in nearly all the black moths and had led, through an unknown mechanism, to the production of dark-colored wings. The researchers dated the insertion to 1819, just as pollution began reshaping the moths' habitat.

Where it stands. This is one well-documented case built on a peer-reviewed 2016 genome study, not proof that transposons usually drive adaptation this cleanly. Researchers still debate how the insertion actually changes wing color at the molecular level. The broader pattern, that transposons have shaped eyes, immune systems and even the placenta across many species, rests on a wider but less tightly dated body of evidence.

Jake Buehler · Quanta Magazine · Sep 2026 ↗
BEHAVIORAL GAME THEORY · a solution concept introduced by Richard McKelvey and Thomas Palfrey

Game Theory That Expects Players To Make Mistakes

Setup. Classical game theory, built around the Nash equilibrium, assumes every player always picks their single best move given what everyone else is doing. Real people do not play that cleanly. They make errors, but the errors are not random noise, they cluster around the choices that are cheap to get wrong.

The finding. Richard McKelvey and Thomas Palfrey built an alternative called quantal response equilibrium, where a strategy's probability of being chosen rises with its payoff rather than being all-or-nothing. A parameter tunes how sharp this gets: near zero, players choose at random, and as it grows large, play converges back to Nash equilibrium. A large-scale analysis of the American television game show The Price Is Right, for example, shows that contestants behavior in the so-called Showcase Showdown, a sequential game of perfect information, can be well explained by an agent quantal response equilibrium (AQRE) model.

Where it stands. The model fits laboratory and real high-stakes data better than pure Nash equilibrium across many published tests. Its own critics have shown it is not falsifiable in general games without extra restrictions, meaning its flexibility can make almost any behavior look consistent with it after the fact.

Richard McKelvey and Thomas Palfrey · Wikipedia ↗
Sep 28, 2026
PSYCHOLOGY · a 2002 study, contested in 2011, reconfirmed with census data in 2015

People Gravitate Toward Anything That Resembles Their Own Name

Setup. People like to feel good about themselves. Psychologists Brett Pelham, Matthew Mirenberg, and John Jones argued in 2002 that this quietly shapes choices unrelated to self-image, an effect they called implicit egotism. It was used to explain nominative determinism, the idea that people gravitate toward jobs that fit their own names.

The finding. Uri Simonsohn attacked the theory in 2011, reanalyzing the same data and calling the name-job correlations "spurious." Pelham and Mauricio Carvallo answered in 2015 with three independent censuses, 1880 and 1940 United States and 1911 England, controlling for gender, ethnicity, and education. They found people disproportionately worked in eleven trades that matched their own surnames: baker, barber, butcher, butler, carpenter, farmer, foreman, mason, miner, painter, and porter. The same data showed people tended to marry partners sharing their birthday number or birth month.

Where it stands. This is a live replication fight, not a settled finding. Simonsohn's critique was serious and forced better controls. Pelham and Carvallo's reply used three independent population datasets, a stronger design than the original lab study. The surname pattern now has real population-scale support. The claimed mechanism, an unconscious pull toward the self, is still inferred from the pattern rather than measured directly.

Pelham, Mirenberg and Jones · Wikipedia, 2002 ↗
HISTORIOGRAPHY · a 1990 thesis contested by historians of medicine since 2003

A Historian's Story About Sex Difference Doesn't Hold Up

Setup. In 1990 historian Thomas Laqueur published Making Sex, arguing Western medicine had for centuries treated female anatomy as an inverted, inferior copy of male anatomy, a "one-sex model," before flipping around the 18th century to a "two-sex model" that treated the sexes as opposite. He read ancient physicians like Galen as believing the vagina was literally an internal penis, the uterus a scrotum, differing only by a lack of bodily heat.

The argument. Laqueur claimed the switch was political, not scientific: Enlightenment thinkers needed to ground the exclusion of women from public life in biology rather than custom, once the French Revolution made appeals to custom unstable.

Where it stands. The thesis has not survived contact with specialists. Michael Stolberg's 2003 article showed explicit anatomical sex difference in print by the early 17th century, at least 200 years before Laqueur's claimed turning point. Katharine Park and Robert Nye argued Laqueur misread Galen, mistaking an explanatory analogy for a claim of literal sameness. Helen King's 2013 book found both models coexisting since antiquity, and historian Monica Green called in 2018 for the field to abandon the framework entirely.

Thomas Laqueur · Making Sex: Body and Gender from the Greeks to Freud, 1990 ↗
ARMS CONTROL · analysis of the nuclear nonproliferation record · Sep 2026

Nuclear Nonproliferation Worked Through Coercion, Not Just Treaties

Setup. AI executives now compare their technology to nuclear weapons: Dario Amodei calls powerful models "weaponizable nuclear materials," and Sam Altman points to the International Atomic Energy Agency as a template. Scholars Christopher David LaRoche and Ankit Panda tested whether the history behind 81 years without nuclear war actually supports copying its methods for AI.

The argument. The record is messier than the analogy assumes. South Korea and Taiwan gave up weapons programs under direct US coercion, not treaty design; Israel bombed Iraqi and Syrian reactors rather than rely on inspections. When states were determined to develop nuclear weapons and could withstand outside pressure, the nonproliferation regime had little power to stop them. India, Israel, North Korea, and Pakistan all managed to build the bomb. AI is also harder to trace: uranium and plutonium are scarce and physically constrained, while a trained model's weights can be copied and run anywhere.

Where it stands. This is an argument from documented history, not a new finding, by authors who are nuclear-policy specialists rather than neutral observers of AI. That coercion, not treaty design, did most of the real work is well supported by the named cases. The weaker claim is predictive: that AI's traceability problem makes a nuclear-style regime unworkable is a reasoned inference from the technology's structure, not yet tested.

Christopher David LaRoche and Ankit Panda · Foreign Affairs · Sep 2026 ↗
SOCIAL PSYCHOLOGY · a finding replicated across six decades since 1961

Groups Don't Average Opinions, They Amplify Them

Setup. In 1961 MIT student James Stoner found something odd: groups made riskier decisions than the average of what their members chose alone, later named the "risky shift." Researchers had expected discussion to average views toward the middle, not push them further out.

The finding. By the late 1960s the pattern was generalized to group polarization: discussion pushes a group's position toward whatever its members already leaned toward, whether the topic is risk or politics. A 1979 study by Charles Lord, Lee Ross, and Mark Lepper showed the same logic applies to evidence itself. Supporters and opponents of capital punishment read identical mixed research, then rated whichever study matched their own view as better conducted. Whichever position they held initially, people tended to hold that position more strongly after reading research that supported it.

Where it stands. Group polarization has replicated across juries, online platforms, and labs for six decades, under two explanations: people shift toward the group's admired position, or they hear mostly one-sided arguments during discussion. Evidence supports both, likely operating together. The 1979 capital-punishment study had an acknowledged methodological flaw, but the broader polarization effect it dramatized has held up well.

James Stoner · Wikipedia, 1961 ↗
BEHAVIORAL ECONOMICS · synthesis of named studies since Asch's 1951 experiments

Copying The Crowd Can Be The Rational Choice

Setup. Herd behavior is usually treated as a failure of reasoning, people copying a crowd instead of thinking for themselves. Economists distinguish this from rational herding, where copying others is the most sensible response to real uncertainty, not a lapse in judgment.

The mechanism. When people believe others hold useful private information, copying the majority becomes a reasonable shortcut. This logic is formalised in models of information cascades, in which each person rationally ignores their own private signal because the weight of prior public choices is more informative. The result is that collectively irrational outcomes, such as financial bubbles or fads, can emerge from individually rational, well-intentioned reasoning. Two biases shape who gets copied: prestige bias favors people who look skilled regardless of relevance, and success bias credits a behavior for an outcome it may not have caused.

Where it stands. The core logic is well established theoretically and traces to real experiments like Solomon Asch's 1951 conformity studies. The harder question, how much real-world herding in markets or medicine is genuinely rational rather than emotional contagion, is less settled. The article itself notes the finance literature leans on price and investment data because it is easy to get, not because it best tests the theory.

unknown · Wikipedia, 1951 ↗
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